Popcorn popping machines for use in theaters, concession stands, and homes are well known. Industrial machines for making large quantities of popcorn, puffed rice, and other expanded food products for wholesale to retailers are also known. One method of industrial scale popcorn popping employs a popping kettle. To make popcorn, unpopped corn kernels and oil are placed in the kettle and heated with a gas burner or electric heating element. The cooking oil coats the kernels and ensures a relatively even distribution of heat throughout the kernel.
Agitating the kernels can prevent them from burning on the bottom of the kettle where the heat is most intense. For this reason, many popcorn machines include some type of agitator that mixes the corn kernels with the cooking oil and ensures even popping. Some machines, for example, include stirring blades that are mounted to a rotating shaft driven by an electric motor. In operation, the stirring blades sweep around the inside of the popping kettle, mixing the kernels with the cooking oil and ensuring the kernels are evenly heated. The agitators also ensure that the kernels remain in motion, which helps prevent burning and aids in uniform heating of the kernels.